The government said it would “look carefully” at Mr Spicer’s 33 recommendations, which also included a need for research into the cultural background of abusers, many of whom in the case of Sanctuary were from a “predominantly Asian or British Minority Ethnic culture or background”.

Mr Spicer, who carried out the serious case review for the Newcastle Safeguarding Adults and Children Boards, said it was clear “adults were being targeted, groomed and exploited” as well as children.

But he said authorities did not have the powers to intervene with adults to stop them “making bad choices” or forming “inappropriate relationships”.

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Media captionOne victim of sexual exploitation in the city says abuse still continues

He said: “Vulnerability is not determined by age and it is likely that extensive abuse of vulnerable adults is taking place across the country unrecognised.”

Operation Sanctuary started in 2014 after a 21-year-old woman with a learning disability told police she had been a victim of sexual exploitation over a long period.

Further reports from two 19-year-old women “confirmed” sexual exploitation was a much larger problem in Newcastle “than previously recognised”.

Mr Spicer said the operation had proved successful but it was only when Northumbria Police and other agencies like Newcastle City Council started looking for the issue they found it.

Image caption David Spicer led the serious case review

He also said the government needs to research the “profiles, motivations and cultural and background influences of perpetrators of sexual exploitation”.

In the Newcastle case, most of the men were British-born but all came from Bangladeshi, Pakistani, Indian, Iraqi, Iranian or Turkish communities.